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Properties

Label 16.0.605...000.2
Degree $16$
Signature $[0, 8]$
Discriminant $6.052\times 10^{23}$
Root discriminant \(30.65\)
Ramified primes $2,3,5,7$
Class number $32$ (GRH)
Class group [4, 8] (GRH)
Galois group $C_4\times C_2^2$ (as 16T2)

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Show commands: Magma / Oscar / PariGP / SageMath

Normalized defining polynomial

sage: x = polygen(QQ); K.<a> = NumberField(x^16 + 21*x^14 + 210*x^12 + 1104*x^10 + 3329*x^8 + 5124*x^6 + 4320*x^4 + 1536*x^2 + 256)
 
gp: K = bnfinit(y^16 + 21*y^14 + 210*y^12 + 1104*y^10 + 3329*y^8 + 5124*y^6 + 4320*y^4 + 1536*y^2 + 256, 1)
 
magma: R<x> := PolynomialRing(Rationals()); K<a> := NumberField(x^16 + 21*x^14 + 210*x^12 + 1104*x^10 + 3329*x^8 + 5124*x^6 + 4320*x^4 + 1536*x^2 + 256);
 
oscar: Qx, x = PolynomialRing(QQ); K, a = NumberField(x^16 + 21*x^14 + 210*x^12 + 1104*x^10 + 3329*x^8 + 5124*x^6 + 4320*x^4 + 1536*x^2 + 256)
 

\( x^{16} + 21x^{14} + 210x^{12} + 1104x^{10} + 3329x^{8} + 5124x^{6} + 4320x^{4} + 1536x^{2} + 256 \) Copy content Toggle raw display

sage: K.defining_polynomial()
 
gp: K.pol
 
magma: DefiningPolynomial(K);
 
oscar: defining_polynomial(K)
 

Invariants

Degree:  $16$
sage: K.degree()
 
gp: poldegree(K.pol)
 
magma: Degree(K);
 
oscar: degree(K)
 
Signature:  $[0, 8]$
sage: K.signature()
 
gp: K.sign
 
magma: Signature(K);
 
oscar: signature(K)
 
Discriminant:   \(605165749776000000000000\) \(\medspace = 2^{16}\cdot 3^{8}\cdot 5^{12}\cdot 7^{8}\) Copy content Toggle raw display
sage: K.disc()
 
gp: K.disc
 
magma: OK := Integers(K); Discriminant(OK);
 
oscar: OK = ring_of_integers(K); discriminant(OK)
 
Root discriminant:  \(30.65\)
sage: (K.disc().abs())^(1./K.degree())
 
gp: abs(K.disc)^(1/poldegree(K.pol))
 
magma: Abs(Discriminant(OK))^(1/Degree(K));
 
oscar: (1.0 * dK)^(1/degree(K))
 
Galois root discriminant:  $2\cdot 3^{1/2}5^{3/4}7^{1/2}\approx 30.645530678223075$
Ramified primes:   \(2\), \(3\), \(5\), \(7\) Copy content Toggle raw display
sage: K.disc().support()
 
gp: factor(abs(K.disc))[,1]~
 
magma: PrimeDivisors(Discriminant(OK));
 
oscar: prime_divisors(discriminant((OK)))
 
Discriminant root field:  \(\Q\)
$\card{ \Gal(K/\Q) }$:  $16$
sage: K.automorphisms()
 
magma: Automorphisms(K);
 
oscar: automorphisms(K)
 
This field is Galois and abelian over $\Q$.
Conductor:  \(420=2^{2}\cdot 3\cdot 5\cdot 7\)
Dirichlet character group:    $\lbrace$$\chi_{420}(1,·)$, $\chi_{420}(197,·)$, $\chi_{420}(71,·)$, $\chi_{420}(349,·)$, $\chi_{420}(223,·)$, $\chi_{420}(419,·)$, $\chi_{420}(293,·)$, $\chi_{420}(169,·)$, $\chi_{420}(43,·)$, $\chi_{420}(239,·)$, $\chi_{420}(113,·)$, $\chi_{420}(307,·)$, $\chi_{420}(181,·)$, $\chi_{420}(377,·)$, $\chi_{420}(251,·)$, $\chi_{420}(127,·)$$\rbrace$
This is a CM field.
Reflex fields:  unavailable$^{128}$

Integral basis (with respect to field generator \(a\))

$1$, $a$, $a^{2}$, $a^{3}$, $a^{4}$, $a^{5}$, $a^{6}$, $a^{7}$, $a^{8}$, $\frac{1}{2}a^{9}-\frac{1}{2}a^{7}-\frac{1}{2}a$, $\frac{1}{4}a^{10}+\frac{1}{4}a^{8}-\frac{1}{2}a^{6}+\frac{1}{4}a^{2}$, $\frac{1}{8}a^{11}+\frac{1}{8}a^{9}-\frac{1}{4}a^{7}+\frac{1}{8}a^{3}$, $\frac{1}{16}a^{12}+\frac{1}{16}a^{10}-\frac{1}{8}a^{8}-\frac{1}{2}a^{6}+\frac{1}{16}a^{4}$, $\frac{1}{32}a^{13}+\frac{1}{32}a^{11}-\frac{1}{16}a^{9}-\frac{1}{4}a^{7}+\frac{1}{32}a^{5}-\frac{1}{2}a^{3}$, $\frac{1}{12058248256}a^{14}+\frac{368923857}{12058248256}a^{12}+\frac{621653215}{6029124128}a^{10}+\frac{627032649}{1507281032}a^{8}-\frac{4746983423}{12058248256}a^{6}-\frac{22016030}{188410129}a^{4}-\frac{374349579}{753640516}a^{2}+\frac{86211877}{188410129}$, $\frac{1}{24116496512}a^{15}+\frac{368923857}{24116496512}a^{13}+\frac{621653215}{12058248256}a^{11}+\frac{627032649}{3014562064}a^{9}-\frac{4746983423}{24116496512}a^{7}+\frac{166394099}{376820258}a^{5}-\frac{374349579}{1507281032}a^{3}+\frac{86211877}{376820258}a$ Copy content Toggle raw display

sage: K.integral_basis()
 
gp: K.zk
 
magma: IntegralBasis(K);
 
oscar: basis(OK)
 

Monogenic:  Not computed
Index:  $1$
Inessential primes:  None

Class group and class number

$C_{4}\times C_{8}$, which has order $32$ (assuming GRH)

sage: K.class_group().invariants()
 
gp: K.clgp
 
magma: ClassGroup(K);
 
oscar: class_group(K)
 

Unit group

sage: UK = K.unit_group()
 
magma: UK, fUK := UnitGroup(K);
 
oscar: UK, fUK = unit_group(OK)
 
Rank:  $7$
sage: UK.rank()
 
gp: K.fu
 
magma: UnitRank(K);
 
oscar: rank(UK)
 
Torsion generator:   \( -1 \)  (order $2$) Copy content Toggle raw display
sage: UK.torsion_generator()
 
gp: K.tu[2]
 
magma: K!f(TU.1) where TU,f is TorsionUnitGroup(K);
 
oscar: torsion_units_generator(OK)
 
Fundamental units:   $\frac{26469}{10141504}a^{14}+\frac{537853}{10141504}a^{12}+\frac{2584575}{5070752}a^{10}+\frac{3156195}{1267688}a^{8}+\frac{66896037}{10141504}a^{6}+\frac{9113817}{1267688}a^{4}+\frac{1766205}{633844}a^{2}-\frac{19642}{158461}$, $\frac{64036989}{24116496512}a^{15}+\frac{1273459029}{24116496512}a^{13}+\frac{6030101247}{12058248256}a^{11}+\frac{7242527033}{3014562064}a^{9}+\frac{155478384413}{24116496512}a^{7}+\frac{23832993713}{3014562064}a^{5}+\frac{1257699553}{188410129}a^{3}+\frac{224590592}{188410129}a$, $\frac{86479971}{24116496512}a^{15}+\frac{1808929163}{24116496512}a^{13}+\frac{8994072825}{12058248256}a^{11}+\frac{11681290437}{3014562064}a^{9}+\frac{274768798627}{24116496512}a^{7}+\frac{49159078287}{3014562064}a^{5}+\frac{17336131275}{1507281032}a^{3}+\frac{798941087}{376820258}a$, $\frac{86479971}{24116496512}a^{15}+\frac{352509}{188410129}a^{14}+\frac{1808929163}{24116496512}a^{13}+\frac{112801663}{3014562064}a^{12}+\frac{8994072825}{12058248256}a^{11}+\frac{1072632015}{3014562064}a^{10}+\frac{11681290437}{3014562064}a^{9}+\frac{2585953825}{1507281032}a^{8}+\frac{274768798627}{24116496512}a^{7}+\frac{1709907615}{376820258}a^{6}+\frac{49159078287}{3014562064}a^{5}+\frac{14891467071}{3014562064}a^{4}+\frac{17336131275}{1507281032}a^{3}+\frac{360607065}{188410129}a^{2}+\frac{798941087}{376820258}a+\frac{182351}{188410129}$, $\frac{160473763}{24116496512}a^{15}+\frac{226815}{376820258}a^{14}+\frac{3343233631}{24116496512}a^{13}+\frac{4493459}{376820258}a^{12}+\frac{16554458883}{12058248256}a^{11}+\frac{84932625}{753640516}a^{10}+\frac{1335976862}{188410129}a^{9}+\frac{405377525}{753640516}a^{8}+\frac{499789880387}{24116496512}a^{7}+\frac{268022505}{188410129}a^{6}+\frac{177828201603}{6029124128}a^{5}+\frac{291585080}{188410129}a^{4}+\frac{31461516631}{1507281032}a^{3}+\frac{451808745}{753640516}a^{2}+\frac{1448458921}{376820258}a-\frac{135818449}{188410129}$, $\frac{107882083}{24116496512}a^{15}-\frac{352509}{188410129}a^{14}+\frac{2267840671}{24116496512}a^{13}-\frac{112801663}{3014562064}a^{12}+\frac{11319913859}{12058248256}a^{11}-\frac{1072632015}{3014562064}a^{10}+\frac{1849679869}{376820258}a^{9}-\frac{2585953825}{1507281032}a^{8}+\frac{350656339267}{24116496512}a^{7}-\frac{1709907615}{376820258}a^{6}+\frac{127611699843}{6029124128}a^{5}-\frac{14891467071}{3014562064}a^{4}+\frac{21927124311}{1507281032}a^{3}-\frac{360607065}{188410129}a^{2}+\frac{507443802}{188410129}a-\frac{182351}{188410129}$, $\frac{160473763}{24116496512}a^{15}+\frac{3343233631}{24116496512}a^{13}+\frac{16554458883}{12058248256}a^{11}+\frac{1335976862}{188410129}a^{9}+\frac{499789880387}{24116496512}a^{7}+\frac{177828201603}{6029124128}a^{5}+\frac{31461516631}{1507281032}a^{3}+\frac{1448458921}{376820258}a+1$ Copy content Toggle raw display (assuming GRH)
sage: UK.fundamental_units()
 
gp: K.fu
 
magma: [K|fUK(g): g in Generators(UK)];
 
oscar: [K(fUK(a)) for a in gens(UK)]
 
Regulator:  \( 3121.7160225 \) (assuming GRH)
sage: K.regulator()
 
gp: K.reg
 
magma: Regulator(K);
 
oscar: regulator(K)
 

Class number formula

\[ \begin{aligned}\lim_{s\to 1} (s-1)\zeta_K(s) =\mathstrut & \frac{2^{r_1}\cdot (2\pi)^{r_2}\cdot R\cdot h}{w\cdot\sqrt{|D|}}\cr \approx\mathstrut &\frac{2^{0}\cdot(2\pi)^{8}\cdot 3121.7160225 \cdot 32}{2\cdot\sqrt{605165749776000000000000}}\cr\approx \mathstrut & 0.15596069172 \end{aligned}\] (assuming GRH)

# self-contained SageMath code snippet to compute the analytic class number formula
 
x = polygen(QQ); K.<a> = NumberField(x^16 + 21*x^14 + 210*x^12 + 1104*x^10 + 3329*x^8 + 5124*x^6 + 4320*x^4 + 1536*x^2 + 256)
 
DK = K.disc(); r1,r2 = K.signature(); RK = K.regulator(); RR = RK.parent()
 
hK = K.class_number(); wK = K.unit_group().torsion_generator().order();
 
2^r1 * (2*RR(pi))^r2 * RK * hK / (wK * RR(sqrt(abs(DK))))
 
# self-contained Pari/GP code snippet to compute the analytic class number formula
 
K = bnfinit(x^16 + 21*x^14 + 210*x^12 + 1104*x^10 + 3329*x^8 + 5124*x^6 + 4320*x^4 + 1536*x^2 + 256, 1);
 
[polcoeff (lfunrootres (lfuncreate (K))[1][1][2], -1), 2^K.r1 * (2*Pi)^K.r2 * K.reg * K.no / (K.tu[1] * sqrt (abs (K.disc)))]
 
/* self-contained Magma code snippet to compute the analytic class number formula */
 
Qx<x> := PolynomialRing(QQ); K<a> := NumberField(x^16 + 21*x^14 + 210*x^12 + 1104*x^10 + 3329*x^8 + 5124*x^6 + 4320*x^4 + 1536*x^2 + 256);
 
OK := Integers(K); DK := Discriminant(OK);
 
UK, fUK := UnitGroup(OK); clK, fclK := ClassGroup(OK);
 
r1,r2 := Signature(K); RK := Regulator(K); RR := Parent(RK);
 
hK := #clK; wK := #TorsionSubgroup(UK);
 
2^r1 * (2*Pi(RR))^r2 * RK * hK / (wK * Sqrt(RR!Abs(DK)));
 
# self-contained Oscar code snippet to compute the analytic class number formula
 
Qx, x = PolynomialRing(QQ); K, a = NumberField(x^16 + 21*x^14 + 210*x^12 + 1104*x^10 + 3329*x^8 + 5124*x^6 + 4320*x^4 + 1536*x^2 + 256);
 
OK = ring_of_integers(K); DK = discriminant(OK);
 
UK, fUK = unit_group(OK); clK, fclK = class_group(OK);
 
r1,r2 = signature(K); RK = regulator(K); RR = parent(RK);
 
hK = order(clK); wK = torsion_units_order(K);
 
2^r1 * (2*pi)^r2 * RK * hK / (wK * sqrt(RR(abs(DK))))
 

Galois group

$C_2^2\times C_4$ (as 16T2):

sage: K.galois_group(type='pari')
 
gp: polgalois(K.pol)
 
magma: G = GaloisGroup(K);
 
oscar: G, Gtx = galois_group(K); G, transitive_group_identification(G)
 
An abelian group of order 16
The 16 conjugacy class representatives for $C_4\times C_2^2$
Character table for $C_4\times C_2^2$

Intermediate fields

\(\Q(\sqrt{-35}) \), \(\Q(\sqrt{3}) \), \(\Q(\sqrt{-105}) \), \(\Q(\sqrt{5}) \), \(\Q(\sqrt{-7}) \), \(\Q(\sqrt{15}) \), \(\Q(\sqrt{-21}) \), \(\Q(\sqrt{3}, \sqrt{-35})\), \(\Q(\sqrt{5}, \sqrt{-7})\), \(\Q(\sqrt{15}, \sqrt{-21})\), \(\Q(\sqrt{3}, \sqrt{5})\), \(\Q(\sqrt{3}, \sqrt{-7})\), \(\Q(\sqrt{5}, \sqrt{-21})\), \(\Q(\sqrt{-7}, \sqrt{15})\), 4.0.55125.1, \(\Q(\zeta_{15})^+\), 4.0.98000.1, \(\Q(\zeta_{20})^+\), 8.0.31116960000.6, 8.0.3038765625.2, 8.0.9604000000.2, 8.0.777924000000.5, \(\Q(\zeta_{60})^+\), 8.0.777924000000.6, 8.0.777924000000.7

Fields in the database are given up to isomorphism. Isomorphic intermediate fields are shown with their multiplicities.

sage: K.subfields()[1:-1]
 
gp: L = nfsubfields(K); L[2..length(b)]
 
magma: L := Subfields(K); L[2..#L];
 
oscar: subfields(K)[2:end-1]
 

Frobenius cycle types

$p$ $2$ $3$ $5$ $7$ $11$ $13$ $17$ $19$ $23$ $29$ $31$ $37$ $41$ $43$ $47$ $53$ $59$
Cycle type R R R R ${\href{/padicField/11.2.0.1}{2} }^{8}$ ${\href{/padicField/13.4.0.1}{4} }^{4}$ ${\href{/padicField/17.4.0.1}{4} }^{4}$ ${\href{/padicField/19.2.0.1}{2} }^{8}$ ${\href{/padicField/23.4.0.1}{4} }^{4}$ ${\href{/padicField/29.2.0.1}{2} }^{8}$ ${\href{/padicField/31.2.0.1}{2} }^{8}$ ${\href{/padicField/37.4.0.1}{4} }^{4}$ ${\href{/padicField/41.2.0.1}{2} }^{8}$ ${\href{/padicField/43.4.0.1}{4} }^{4}$ ${\href{/padicField/47.4.0.1}{4} }^{4}$ ${\href{/padicField/53.4.0.1}{4} }^{4}$ ${\href{/padicField/59.2.0.1}{2} }^{8}$

In the table, R denotes a ramified prime. Cycle lengths which are repeated in a cycle type are indicated by exponents.

# to obtain a list of $[e_i,f_i]$ for the factorization of the ideal $p\mathcal{O}_K$ for $p=7$ in Sage:
 
p = 7; [(e, pr.norm().valuation(p)) for pr,e in K.factor(p)]
 
\\ to obtain a list of $[e_i,f_i]$ for the factorization of the ideal $p\mathcal{O}_K$ for $p=7$ in Pari:
 
p = 7; pfac = idealprimedec(K, p); vector(length(pfac), j, [pfac[j][3], pfac[j][4]])
 
// to obtain a list of $[e_i,f_i]$ for the factorization of the ideal $p\mathcal{O}_K$ for $p=7 in Magma:
 
p := 7; [<pr[2], Valuation(Norm(pr[1]), p)> : pr in Factorization(p*Integers(K))];
 
# to obtain a list of $[e_i,f_i]$ for the factorization of the ideal $p\mathcal{O}_K$ for $p=7$ in Oscar:
 
p = 7; pfac = factor(ideal(ring_of_integers(K), p)); [(e, valuation(norm(pr),p)) for (pr,e) in pfac]
 

Local algebras for ramified primes

$p$LabelPolynomial $e$ $f$ $c$ Galois group Slope content
\(2\) Copy content Toggle raw display 2.8.8.1$x^{8} + 8 x^{7} + 32 x^{6} + 82 x^{5} + 148 x^{4} + 184 x^{3} + 137 x^{2} + 44 x + 5$$2$$4$$8$$C_4\times C_2$$[2]^{4}$
2.8.8.1$x^{8} + 8 x^{7} + 32 x^{6} + 82 x^{5} + 148 x^{4} + 184 x^{3} + 137 x^{2} + 44 x + 5$$2$$4$$8$$C_4\times C_2$$[2]^{4}$
\(3\) Copy content Toggle raw display 3.8.4.1$x^{8} + 4 x^{7} + 16 x^{6} + 36 x^{5} + 94 x^{4} + 116 x^{3} + 144 x^{2} + 36 x + 229$$2$$4$$4$$C_4\times C_2$$[\ ]_{2}^{4}$
3.8.4.1$x^{8} + 4 x^{7} + 16 x^{6} + 36 x^{5} + 94 x^{4} + 116 x^{3} + 144 x^{2} + 36 x + 229$$2$$4$$4$$C_4\times C_2$$[\ ]_{2}^{4}$
\(5\) Copy content Toggle raw display 5.8.6.1$x^{8} + 16 x^{7} + 104 x^{6} + 352 x^{5} + 674 x^{4} + 784 x^{3} + 776 x^{2} + 928 x + 721$$4$$2$$6$$C_4\times C_2$$[\ ]_{4}^{2}$
5.8.6.1$x^{8} + 16 x^{7} + 104 x^{6} + 352 x^{5} + 674 x^{4} + 784 x^{3} + 776 x^{2} + 928 x + 721$$4$$2$$6$$C_4\times C_2$$[\ ]_{4}^{2}$
\(7\) Copy content Toggle raw display 7.8.4.1$x^{8} + 38 x^{6} + 8 x^{5} + 395 x^{4} - 72 x^{3} + 1026 x^{2} - 872 x + 401$$2$$4$$4$$C_4\times C_2$$[\ ]_{2}^{4}$
7.8.4.1$x^{8} + 38 x^{6} + 8 x^{5} + 395 x^{4} - 72 x^{3} + 1026 x^{2} - 872 x + 401$$2$$4$$4$$C_4\times C_2$$[\ ]_{2}^{4}$